// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/base/priority_queue.h"

#include <cstddef>

#include "testing/gtest/include/gtest/gtest.h"

namespace net {

namespace {

    typedef PriorityQueue<int>::Priority Priority;
    const Priority kPriorities[] = { 2, 1, 2, 0, 4, 3, 1, 4, 0 };
    const Priority kNumPriorities = 5; // max(kPriorities) + 1
    const size_t kNumElements = arraysize(kPriorities);
    const int kFirstMinOrder[kNumElements] = { 3, 8, 1, 6, 0, 2, 5, 4, 7 };
    const int kLastMaxOrderErase[kNumElements] = { 7, 4, 5, 2, 0, 6, 1, 8, 3 };
    const int kFirstMaxOrder[kNumElements] = { 4, 7, 5, 0, 2, 1, 6, 3, 8 };
    const int kLastMinOrder[kNumElements] = { 8, 3, 6, 1, 2, 0, 5, 7, 4 };

    class PriorityQueueTest : public testing::Test {
    protected:
        PriorityQueueTest()
            : queue_(kNumPriorities)
        {
        }

        void SetUp() override
        {
            CheckEmpty();
            for (size_t i = 0; i < kNumElements; ++i) {
                EXPECT_EQ(i, queue_.size());
                pointers_[i] = queue_.Insert(static_cast<int>(i), kPriorities[i]);
                EXPECT_FALSE(queue_.empty());
            }
            EXPECT_EQ(kNumElements, queue_.size());
        }

        void CheckEmpty()
        {
            EXPECT_TRUE(queue_.empty());
            EXPECT_EQ(0u, queue_.size());
            EXPECT_TRUE(queue_.FirstMin().is_null());
            EXPECT_TRUE(queue_.LastMin().is_null());
            EXPECT_TRUE(queue_.FirstMax().is_null());
            EXPECT_TRUE(queue_.LastMax().is_null());
        }

        PriorityQueue<int> queue_;
        PriorityQueue<int>::Pointer pointers_[kNumElements];
    };

    TEST_F(PriorityQueueTest, AddAndClear)
    {
        for (size_t i = 0; i < kNumElements; ++i) {
            EXPECT_EQ(kPriorities[i], pointers_[i].priority());
            EXPECT_EQ(static_cast<int>(i), pointers_[i].value());
        }
        queue_.Clear();
        CheckEmpty();
    }

    TEST_F(PriorityQueueTest, FirstMinOrder)
    {
        for (size_t i = 0; i < kNumElements; ++i) {
            EXPECT_EQ(kNumElements - i, queue_.size());
            // Also check Equals.
            EXPECT_TRUE(queue_.FirstMin().Equals(pointers_[kFirstMinOrder[i]]));
            EXPECT_EQ(kFirstMinOrder[i], queue_.FirstMin().value());
            queue_.Erase(queue_.FirstMin());
        }
        CheckEmpty();
    }

    TEST_F(PriorityQueueTest, LastMinOrder)
    {
        for (size_t i = 0; i < kNumElements; ++i) {
            EXPECT_EQ(kLastMinOrder[i], queue_.LastMin().value());
            queue_.Erase(queue_.LastMin());
        }
        CheckEmpty();
    }

    TEST_F(PriorityQueueTest, FirstMaxOrder)
    {
        PriorityQueue<int>::Pointer p = queue_.FirstMax();
        size_t i = 0;
        for (; !p.is_null() && i < kNumElements;
             p = queue_.GetNextTowardsLastMin(p), ++i) {
            EXPECT_EQ(kFirstMaxOrder[i], p.value());
        }
        EXPECT_TRUE(p.is_null());
        EXPECT_EQ(kNumElements, i);
        queue_.Clear();
        CheckEmpty();
    }

    TEST_F(PriorityQueueTest, GetNextTowardsLastMinAndErase)
    {
        PriorityQueue<int>::Pointer current = queue_.FirstMax();
        for (size_t i = 0; i < kNumElements; ++i) {
            EXPECT_FALSE(current.is_null());
            EXPECT_EQ(kFirstMaxOrder[i], current.value());
            PriorityQueue<int>::Pointer next = queue_.GetNextTowardsLastMin(current);
            queue_.Erase(current);
            current = next;
        }
        EXPECT_TRUE(current.is_null());
        CheckEmpty();
    }

    TEST_F(PriorityQueueTest, FirstMaxOrderErase)
    {
        for (size_t i = 0; i < kNumElements; ++i) {
            EXPECT_EQ(kFirstMaxOrder[i], queue_.FirstMax().value());
            queue_.Erase(queue_.FirstMax());
        }
        CheckEmpty();
    }

    TEST_F(PriorityQueueTest, LastMaxOrderErase)
    {
        for (size_t i = 0; i < kNumElements; ++i) {
            EXPECT_EQ(kLastMaxOrderErase[i], queue_.LastMax().value());
            queue_.Erase(queue_.LastMax());
        }
        CheckEmpty();
    }

    TEST_F(PriorityQueueTest, EraseFromMiddle)
    {
        queue_.Erase(pointers_[2]);
        queue_.Erase(pointers_[3]);

        const int expected_order[] = { 8, 1, 6, 0, 5, 4, 7 };

        for (size_t i = 0; i < arraysize(expected_order); ++i) {
            EXPECT_EQ(expected_order[i], queue_.FirstMin().value());
            queue_.Erase(queue_.FirstMin());
        }
        CheckEmpty();
    }

    TEST_F(PriorityQueueTest, InsertAtFront)
    {
        queue_.InsertAtFront(9, 2);
        queue_.InsertAtFront(10, 0);
        queue_.InsertAtFront(11, 1);
        queue_.InsertAtFront(12, 1);

        const int expected_order[] = { 10, 3, 8, 12, 11, 1, 6, 9, 0, 2, 5, 4, 7 };

        for (size_t i = 0; i < arraysize(expected_order); ++i) {
            EXPECT_EQ(expected_order[i], queue_.FirstMin().value());
            queue_.Erase(queue_.FirstMin());
        }
        CheckEmpty();
    }

} // namespace

} // namespace net
